Efficient flame-retardant biomass aerogel endowed with graphene oxide interconnected networks for ultrasensitive fire warning.

• A fire-alarm biomass aerogel was prepared by freeze-drying method. • The composite aerogel displays excellent flame-retardant performance. • This fire-alarm aerogel provides early fire warning detection. Flame-retardant thermal insulation materials (TIMs) with a function of fire warning will play a critical role in the fields of sustainable energy saving and fire safety. Herein, we fabricated a fire-alarm aerogel based on biomass sodium alginate and hydroxyapatite, introduced with graphene oxide. This aerogel exhibits good thermal insulating properties due to its porous network. The composite aerogel displays good flame-retardant performance and can provide early fire warning detection. At room temperature, the aerogel is electrically insulating, but it switches to an electrical state when exposed to flame. The aerogel connected with an alarm light can give ultrafast response time (within 1.5 s) and sustained warning time (over 60 s) under sudden fire attacks. This modified aerogel provides a promising strategy for the functional application of TIMs. [ABSTRACT FROM AUTHOR]